Field of the Invention
The present invention relates to a method of manufacturing a sheet having needle-like protrusions.
Description of the Related Art
In recent years, as an example of a sheet having needle-like protrusions, a transdermal absorption sheet including a plurality of needle-like protrusions (referred to as micro needles) containing a medicine has been used to deliver the medicine into a skin. Typically, the transdermal absorption sheet is pressed on the skin to insert the needle-like protrusions into the skin, and then the medicine in the needle-like protrusions is delivered into the skin.
Various methods have been provided for manufacturing this kind of transdermal absorption sheet. For example, WO 2014/077242A1 discloses a method of filling two-dimensionally arranged needle-like recessed portions with a liquid medicine containing a medicine by repeating the following: a filling operation in which a solution (liquid medicine) containing the medicine is supplied to a mold from a liquid feeder and one or more needle-like recessed portions are filled with the solution containing the medicine while a nozzle tip of a nozzle adjusted to a position above needle-like recessed portions is pressed so as to be brought into contact with a surface of the mold at a desired pressing force; and a moving operation in which the nozzle is moved relatively to the mold while the nozzle tip and the surface of the mold are in contact with each other. This enables the needle-like recessed portions to be efficiently filled with the liquid medicine by discharging only a necessary amount of the liquid medicine while the nozzle is pressed on the surface of the mold. As a result, the medicine can be concentrated into the needle-like protrusions, and transdermal absorption sheets can be manufactured with high production efficiency.